The present invention is directed generally to improved apparatus and techniques for measuring geotechnical properties of soil materials and more particularly to an improved multi-blade vane apparatus adapted for this purpose.
In the past, it was common to measure the geotechnical properties of soil materials in a laboratory by test procedures applied to a soil sample. Problems associated with common laboratory procedures, including unrealistic boundary conditions and disturbance as a result of sampling, have made the use of insitu methods more appealing. These methods have recently become a major interest of consulting engineers. The main problem with insitu testing has been the relatively high cost, which therefore limits its extended application.
Accordingly, a primary object of the present invention is to provide an improved apparatus and method for insitu measurement of geotechnical properties of soil materials.
Another object is to provide an improved multi-blade vane apparatus for the measurement of soil properties.
Another object is to provide a multi-blade vane apparatus including electrical pressure sensors for continuously monitoring stress while the vane is being inserted into the ground.
Another object is to provide a multi-blade vane apparatus wherein at least two blades have pressure sensors placed so as to face in opposite rotational directions.
Another object is to provide a multi-blade vane apparatus including a series of independent levels of blades of different thicknesses.
Another object is to provide an improved apparatus and method for obtaining discrete values of soil friction angle and cohesion.
A further object is to provide an improved method and apparatus for measuring the time-deformation characteristics or creep behavior of soils.
A further object is to provide an improved apparatus and method for measuring dynamic soil response for use in earthquake analysis and design of foundations for machine vibrations, etc.
Finally, a further object is to provide an improved multi-blade vane apparatus which is simple and rugged in construction, economical to manufacture and efficient in operation.